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Abstract
Introduction of the grape phylloxera (Phylloxera vitifoliae Fitch) into the vinifera grape growing areas of the world over 100 years ago forced viticulturalists to use resistant rootstocks from central North America. This aphid destroyed more than 2,500,000 acres of vineyards in France alone only 25 years after it was introduced. Control measures other than resistant rootstocks were inadequate for phylloxera. Extensive rootstock development programs have been underway for over 100 years. The North American species, which are generally the most resistant, were studied for their adaptability to soil climate, compatability with vinifera scions, and propagation characteristics. The presently-used rootstocks originated from these studies and breeding programs. The primary objectives of the earlier workers were phylloxera resistance, tolerance to lime induced chlorosis, ease of rooting and grafting, and desirable effect on the yield and quality of scion cultivars. More recently root knot nematode resistance was incorporated in rootstocks (19, 23, 24).
Abstract
Nine cultivars/selections of muscadine grapes (Vitis rotundifolia Michx.) were stored for 49 days at O°C in 6 liter telescoping, corrugated-cardboard shipping containers with polyethylene liners, and 3 types of commercially available SO2 generators. Susceptibility to decay during storage varied greatly among selections (7 to 82% decay without SO2). The SO2 generators produced up to 29 ppm SO2 and all 3 types reduced decay. The genotypes also varied widely in their tolerance of SO2. Placement of newspaper in the shipping containers reduced the concentrations of SO2, reduced SO2 damage to the fruit by up to 74%, and had an inconsistent influence on the development of decay. Fruit of selection NC 67A015-17 appeared to be the best suited for long-term storage.
Abstract
Eighteen lines of Euvitis grapes in 1980, and 30 in 1981, were stored for 9 weeks at 0°C in 5.7-liter telescoping, corrugated cardboard shipping containers with polyethylene liners, with and without commercially available sulfur dioxide (SO2) generators (1 in 1980; 2 in 1981). Decay during storage without SO2 varied greatly among lines (2% to 81% in 1980 and 0% to 62% in 1981). The generator producing SO2 for the entire 9 weeks in 1981 eliminated decay of most grape lots. By comparison, the generators producing SO2 for only 2 weeks permitted 4 times as much decay. Two weeks of SO2, however, permitted only one-fifth as much decay as that associated with no SO2 during storage. Both generators reduced degradation of appearance and flavor of the grapes. The long-term generator was associated with more SO2 damage to the fruit than was the short-term generator. The lines varied widely in tolerance to SO2. SO2 damaged the fruit by entering openings in their surfaces caused by stem tears and cracks.
Abstract
‘Nesbitt’ is a black-fruited muscadine grape (Vitis rotundifolia Michx.) released by the North Carolina Agricultural Research Service. ‘Nesbitt’ is named in memory of the late Dr. William B. Nesbitt, who was instrumental in muscadine grape improvement.
Abstract
‘Sterling’ is a bronze-fruited Vitis rotundifolia Michx. cultivar released by the North Carolina Agricultural Research Service. It is perfect-flowered, self-fruitful, productive, winter-hardy in muscadine growing areas, vigorous and resistant to berry shatter. When ripe, it picks with a reasonably good stem scar and has 6.5-g fruit. ‘Sterling’ is suited for pick-your-own and fresh fruit sales and can be made into a white wine comparable to that of ‘Scuppemong’ and ‘Carlos’.
Abstract
Eight lines (2 cultivars and 6 selections) of Euvitis grapes in 1982 were stored for 4, 6, 7, and 8 weeks at 0° ± 0.5°C without sulfur dioxide (SO2) generators and for 4, 8, 12, 16, and 20 weeks with SO2 generators in 5.7-liter telescoping, corrugated cardboard shipping containers with polyethylene liners. Grapes stored without SO2 were of poorer appearance after 4 weeks than those stored with SO2 after 8 weeks. After 16 weeks of storage with SO2, 4 of the 8 lines still had appearance ratings similar to those before storage. Overall, good flavor was maintained over 7 weeks without SO2 and over 12 weeks with SO2. During 8 weeks of storage without SO2, 6 of the 8 lines developed 23% to 60% decay. In contrast, 6 of the 8 lines stored with SO2 for 16 weeks developed 3% or less decay. SO2 injury (percentage by number) ranged from 0% to 59% but was judged to be objectionable in flavor or appearance in only 2 instances. All lines stored well for 12 weeks with SO2. Of the 8 lines, ‘Suffolk Red’ was judged to be outstanding. After 20 weeks of storage with SO2, ratings of its appearance and flavor were equal to those before storage; decay was only 3.5%.
Abstract
‘Dixie’ is a bronze muscadine grape, Vitis rotundifolia Michx., released jointly by the North Carolina Agricultural Experiment Station and the Florida Agricultural Experiment Station in March, 1976. The ‘Dixie’ grape is high yielding, vigorous, self-fertile and useful for fresh fruit consumption (Fig. 1).
Abstract
‘Noble’ is a black-fruited Vitis rotundifolia Michx., cultivar released by the North Carolina Agricultural Experiment Station. It is perfect-flowered, self-fruitful, high yielding, winter hardy, vigorous and resistant to berry shattering. Fruits of ‘Noble’ can be made into good to excellent red muscadine wine, unfermented juice and jelly, and are of good table quality.
Abstract
Fruit extracts of Lycopersicon esculentum cv. Tiny Tim were found to contains α- and β-galactosidase, a- and β-glucosidase, α- and β-mannosidase, and α- and β-xylosidase activities. All of these enzymes either declined or remained constant in concentration during fruit development and ripening. Activities of β-glucosidase and α-galactosidase were found to be associated with isolated cell wall fragments. No evidence was found for an increase in concentration of the enzymes in the cell wall during ripening. The probability that these enzymes are not involved in fruit softening is discussed.
Abstract
Individual and total sugar and organic acid concn in the juice of 12 cultivars of muscadine grapes (Vitis rotundifolia Michx.) were determined in each of 3 years. Fructose ranged from 3.35 to 9.28% and averaged 5.51%; glucose 3.52 to 7.70% and averaged 5.16%; sucrose 0 to 5.20% and averaged 1.89%; soluble solids 10.20 to 17.85% and averaged 13.21%; malate 0.17 to 1.16% and averaged 0.50%; tartrate 0.15 to 0.52 and averaged 0.26%; citrate ranged from a trace to 0.06% and averaged 0.04%; total titratable acidity 0.39 to 1.549% and averaged 0.839%; pH ranged from 3.50 to 2.88. ‘Roanoke’ was significantly lower in soluble solids (11.18%) than most of the other cultivars over the 3-year period. It was also exceptionally high in malic acid (0.70%) and contained significantly more malate than 7 other cultivars. ‘Roanoke’ and ‘Pamlico’ averaged the highest titratable acidities with 1.099 and 1.049%, respectively. ‘Magoon’ contained significantly more tartrate (0.41%) than all other cultivars except ‘Hunt’. When total titratable acidity values for the 12 cultivars were pooled for each season, it was apparent that yearly differences in these values were primarily due to differences in malate levels since tartrate levels were similar in each of the 3 seasons.